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    #16
    Originally posted by HaBe2305 View Post

    Understood, great, thank you very much again! Please let me know if you find anything or if I could support you by trying something with that.

    I've made some extensions already that I think would be interesting for others as well, so maybe you'd want to include them in the next update (simple and fast to add).

    I've added a switch to the example game mode (and an additional checkbox to the HUD for it) that uses the actual delta time per tick for adding to UTCTime if enabled, so everything will move in realtime independend from framerate. DeltaTime could also be multiplied with IterateTimeSpan as well for the same benefit.

    I also extended the SolarSystemMoonEarth blueprint to always face the earth actor (PlanetOrbiting) using a simple FindLookAtRotation. Since that's one of the main features of our moon, I think that should definitely be included in anything astronomy.

    If you'd want to extend it a bit further with a useful function, it would be nice to get a rotator from the lib that rotates for example a skybox so that the center of our galaxy would be at the correct position, or at least a vector that points in the direction of the milkyway center, if that's even doable. Just suggesting and thinking out loud right now. I'm sure it's nothing trivial in this regard.

    And now for my last question on my list so far. Does the BSP Ephemeris data also come with actual planet rotations? I've found that GetEarthRotator function in the Earth BP only, so my guess is you're calculating earth rotation differently and it's not doable for the other planets because of lacking data, right?

    For the 4.23 update I've added moon and planet rotations, they are generally accurate to about 0.1 degrees. Rotations are only available when using the JPL DE ephemeris data. The updated example project has the rotation data added. To get the rotation data, call 'Get Object Orientation' from a JPL DE ephemeris pointer, and it will return an axis and rotation in degrees. Here is an example on how to pull the rotations in blueprints and set the rotation of a planet:

    Click image for larger version

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    For the stars in the solar system, generating the star field with the Only Celestial option is the correct method.

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      #17
      Originally posted by dingtech View Post


      For the 4.23 update I've added moon and planet rotations, they are generally accurate to about 0.1 degrees. Rotations are only available when using the JPL DE ephemeris data. The updated example project has the rotation data added. To get the rotation data, call 'Get Object Orientation' from a JPL DE ephemeris pointer, and it will return an axis and rotation in degrees. Here is an example on how to pull the rotations in blueprints and set the rotation of a planet:

      For the stars in the solar system, generating the star field with the Only Celestial option is the correct method.
      Perfect, thank you so much for your continued support!
      As a first tiny give back, here's a little screenshot of what I'm using your plugin for. Plotting the orbits was a breeze after understanding how to use your lib. I love it.

      Click image for larger version

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      The only thing I can't get right yet is having the stars correctly aligned in regard to the ecliptic. It only appears correct (compared to an online astronomy resource) when using the equatorial plane (with sun as central body and oberserver location being geocenter), but then the planet orbits are tilted to the world's XY-plane. So right now it seems to me that star positions are always relative to earth no matter what, but I could be wrong.
      Anyways, what I'm after wouldn't be possible for me to achieve without your work, so I'm really grateful.

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        #18
        Originally posted by HaBe2305 View Post

        Perfect, thank you so much for your continued support!
        As a first tiny give back, here's a little screenshot of what I'm using your plugin for. Plotting the orbits was a breeze after understanding how to use your lib. I love it.

        Click image for larger version

Name:	Unbenannt1.png
Views:	23
Size:	378.5 KB
ID:	1667061




        The only thing I can't get right yet is having the stars correctly aligned in regard to the ecliptic. It only appears correct (compared to an online astronomy resource) when using the equatorial plane (with sun as central body and oberserver location being geocenter), but then the planet orbits are tilted to the world's XY-plane. So right now it seems to me that star positions are always relative to earth no matter what, but I could be wrong.
        Anyways, what I'm after wouldn't be possible for me to achieve without your work, so I'm really grateful.
        You're right, it will plot stars based on the earth equator plane, so if you're using the ecliptical plane for the solar system it will be off. Ill look into adding that for the next version. If you are using instanced static meshes, a quick fix could be to just apply a rotation of 22.5 degrees along the Pitch axis (the first FRotator value, so (22.5,0,0)) to the StarManager actor which will rotate all the child InstancedStaticMeshes.

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          #19
          For the next update, I am adding the ability to process and get orbital data from TLE (Two Line Element) sets. TLEs describe the orbit of a satellite around Earth. They are published by US Space Command and are available for download at https://www.space-track.org/.

          Video preview:

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